idr test suite: Take RCU read lock in idr_find_test_1

[ Upstream commit 703586410da69eb40062e64d413ca33bd735917a ]

When run on a single CPU, this test would frequently access already-freed
memory.  Due to timing, this bug never showed up on multi-CPU tests.

Reported-by: Chris von Recklinghausen <crecklin@redhat.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
1 file changed